Show labels for subtree root nodes

This commit is related to the recent PR #1501 which hid (non-aa) labels
depending on their in-view tip-fraction. Here if the label is on the
root of a subtree then we always show it (unless the label is "aa" as
these can be very long).

src/components/tree/phyloTree/labels.js

@@ -85,6 +85,11 @@ const createBranchLabelVisibility = (key, layout, totalTipsInView) => (d) => {
   if (d.n.tipCount > magicTipFractionToShowBranchLabel * totalTipsInView) {
     return "visible";
   }
+  /* if the label is on the root of a subtree then always show it
+  (unless the label is "aa" as these can be very long) */
+  if (key!=='aa' && (d.n.name===d.n.parent.name || d.n.parent.name==="__ROOT")) {
+    return "visible";
+  }
   return "hidden";
 };